Cardiology - Atrial Fibrillation

Question 1

Why can AF increase the risk of thrombus formation?

Answer 1

Uncoordinated atrial activity causing blood to stagnate in the atria

5x higher risk in AF for a stroke

Question 2

What lifestyle factors can cause AF?

Answer 2

Alcohol
Caffeine

Question 3

What are the most common causes of AF?

Answer 3

SMITH

Sepsis
Mitral valve pathology
Ischaemic heart disease
Thyrotoxicosis
Hypertension

Question 4

What is the key examination finding in AF?

Answer 4

Irregularly irregular pulse

May also be ventricular ectopics

Question 5

What happens to ventricular ectopics during exercise?

Answer 5

Ventricular ectopics disappear when heart rate is high enough and heart rate becomes normal

Question 6

What are the ECG findings for AF?

Answer 6

Absent P waves
Narrow QRS complex tachycardia
Irregularly irregular

Question 7

What is paroxysmal atrial fibrillation?

Answer 7

Episodes of AF that reoccur and spontaneously resolve back to sinus rhythm

Episodes last between 30 seconds and 48 hours

Question 8

What investigations are used for suspected paroxysmal AF?

Answer 8

24 hour ambulatory ECG (Holter monitor)
Cardiac event recorder (lasts 1-2 weeks)

Question 9

What is valvular atrial fibrillation?

Answer 9

AF with significant mitral stenosis or a mechanical heart valve

Assumption is that AF has been caused by valvular issue

Question 10

How is AF managed?

Answer 10

Rate or rhythm control
Anticoagulation to prevent strokes

Question 11

How do ventricles fill in AF?

Answer 11

Suction and gravity as atrial contractions are not coordinated

So higher heart rate less time for filling, reducing CO

Rate control to bring heart rate down to increase filling

Question 12

When should patients with AF not be given a rate control as first line?

Answer 12

A reversible cause for AF

New onset within 48 hours

Heart failure caused by AF

Symptoms despite being controlled well

Question 13

What options are used for rate control in AF?

Answer 13

Beta blocker (atenolol or bisoprolol)
Calcium-channel blocker (diltiazem or verapamil)
Digoxin

Question 14

When is rhythm controlled offered to AF patients?

Answer 14

Reversible cause
New onset within 48 hours
Heart failure due to AF
Symptoms despite being controlled well

Question 15

What options are used for rhythm control?

Answer 15

Cardioversion
Long-term rhythm control with medications

Question 16

When is immediate vs delayed cardioversion used?

Answer 16

Immediate
- Present for less than 48 hours
- Causes life-threatening haemodynamic instability

Delayed
- AF present for more than 48 hours and stable
- Patient should be anticoagulated for at least 3 weeks
- If patient has developed a clot in the atria reverting to sinus can mobilise the clot

Question 17

What is used for immediate cardioversion?

Answer 17

Flecainide
Amiodarone (drug of choice with structural heart disease)
Electrical cardioversion

Question 18

What is used for long-term rhythm control whilst waiting for cardioversion?

Answer 18

Beta blockers- first line

Dronedarone- second line, maintaining normal rhythm where patients have had successful cardioversion

Amiodarone- HF or LV dysfunction

Question 19

How is paroxysmal AF managed?

Answer 19

Flecainide is used when the patient feels symptoms are starting

Risk of flecainide converting AF into flutter with 1:1 AV conduction causing a very fast ventricular rate

Question 20

What is ablation used for?

Answer 20

Where drug treatment for rate or rhythm is not adequate or tolerated

Left atrial ablation (remove abnormal electrical pathways)

or

AVN ablation and permanent pacemaker

Anticoagulation is still needed

Question 21

What anticoagulants are used for AF?

Answer 21

First line
DOACs e.g. rivaroxaban

Second line
Warfarin- if DOACs are contraindicated

Question 22

What is the mechanism of action of Dabigatran?

Answer 22

Direct thrombin inhibitor

Question 23

How often are DOACs taken?

Answer 23

Apixaban and dabigatran
Twice daily

Edoxaban and rivaroxaban
Once daily

Question 24

What agents can be used to reverse effects in uncontrolled life-threatening bleeding due to DOACs?

Answer 24

Andexanet alfa (apixaban and rivaroxaban)

Idarucizumab (dabigatran)

Question 25

What are the advantages of DOACs vs Warfarin?

Answer 25

No monitoring needed
No issues with time in therapeutic range
No major interaction problems
Better at preventing strokes in AF
Lower bleeding risk

Question 26

What is the INR (international normalised ration)?

Answer 26

Prothrombin time of an average healthy adult

INR of 1 is normal

INR target for AF is 2-3

Question 27

What is TTR (time in therapeutic range)?

Answer 27

Percentage of time that INR is in target range

If the INR is too low patient is at risk of stroke

Too high patient is at risk of bleeding

Question 28

What can be used to reverse effects of warfarin?

Answer 28

Vitamin K

Question 29

What is CHA2DS2VASc for?

Answer 29

Tool used to assess if a patient with AF should start anticoagulation

C– Congestive heart failure
H – Hypertension
A2 – Age above 75
D – Diabetes
S2 – Stroke or TIA previously
V – Vascular disease
A – Age 65 – 74
S – Sex (female)

0- No anticoagulation
1- Consider in men (women automatically score 1)
2 - Offer anticoagulation

Question 30

What is an ORBIT score used for?

Answer 30

Assessing risk of major bleeding in patients with AF taking anticoagulation

Over 75
Renal impairment (GFR < 60)
Bleeding previously (GI or intracranial bleeding
Iron (low Hb or haematocrit)
Taking antiplatelet medication

Question 31

What is left atrial appendage occlusion?

Answer 31

Left atrial appendage is a small pouch where thrombi commonly form

Occlusion is where the septum is punctured to access the LA and a plug is placed to prevent blood entering that area